June 22, 2008
June 22, 2008
June 25, 2008
Electrical and Computer
13.270.1 - 13.270.11
“Building the Largest Cantenna in Kansas: An Interdisciplinary Collaboration between Engineering Technology Programs”
This paper describes the design and development of a large 20 dBi (decibels isotropic) Wi-Fi antenna for a class project in the Communication Circuit Design course. This large antenna is based on smaller Wi-Fi antennas commonly referred to as cantennas (gain of about 10 dBi). The smaller version is made with a single can (3-4 inches) in diameter and an appropriately placed feed probe. Our version consists of several progressively larger cylindrical sections connected together by 34 degree flared sections (3 inches long). The first cylindrical section has a diameter of 4 inches and the last flared section has a diameter of about 36 inches. The overall length of the antenna is about 5 feet long. While the antenna was designed by electronic and computer engineering technology (ECET) students, mechanical engineering technology (MET) students took charge of building it under the supervision of their MET instructor. The structure was built by spot welding laser-cut pieces of sheet metal. ECET students made experimental measurements to verify the predicted gain and functionality.
The design of the large Cantenna (Figure 1) was taken up by students as a class project for the Communication Circuit Design (ECET 420) course. Chief among the motivational factors influencing their choice seemed to be a desire to learn more about cantennas that could potentially help them share internet access with their friends that lived reasonably close. In the early part of the research cycle we came upon the world record1 for "unamplified" Wi-Fi distance (125 miles). This feat was accomplished by linking two dish antennas (10 feet and 11 feet) in diameter. Each antenna was attached to a Zcom PCMCIA card with a built in power of 300mW. This record influenced the design team to start thinking about building a high-gain Wi-Fi antenna that would be able to communicate over several miles.
Our design did not attempt to match the records for distance. We were interested in building the largest known antenna based on the standard cantenna2 design, using some of the same methodologies.
From the point of view of a communication design course, the construction of any antenna is a good way to learn about impedance matching, guided wave propagation and the radiation characteristics of antennas. Furthermore, the building of a high gain antenna with real world application and record dimensions appealed to all involved. The paper will also comment on student enthusiasm and teamwork in this interdisciplinary endeavor. The sections to follow cover all aspects of antenna development, including
Khan, S., & Spaulding, G. (2008, June), Building The Largest Cantenna In Kansas: An Interdisciplinary Collaboration Between Engineering Technology Programs Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. https://peer.asee.org/3516
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